In the present state of the art, the clamps are disposed circumferentially end-to-end so as to constitute annular clamping means that extend over 360°. Each clamp is of an angular extent or width that is not less than that of a ring sector, with the number of clamps thus being less than or equal to the number of ring sectors.
When each clamp has an angular extent or width that is equal to that of the ring sectors, each clamp is generally engaged on the circumferential rim of a single ring sector so that the lateral faces at the circumferential ends of the clamp are substantially in alignment with the longitudinally-extending edges of the ring sector.
Each clamp is engaged on the casing rail and on the circumferential rim of the ring sector with a certain amount of radial prestress. In operation, a relatively large temperature gradient arises in the radial direction within each ring sector, thereby causing the ring sector to “unbend”. This phenomenon gives rise essentially to an increase in the radius of curvature of the ring sector, thereby increasing stress in the middle portion of the clamp, which can reduce its lifetime.